Masking process and mask set

Abstract

A masking process and a mask set. The masking process includes: aligning a first mask with a stage carrying a substrate to be patterned; forming a first layer structure and a first overlay correction pattern on the substrate to be patterned by using the first mask; correcting with an image sensor and the first overlay correction pattern; aligning a second mask with the stage; forming a second layer structure and a second overlay correction pattern on the substrate to be patterned by using the second mask; and correcting with the image sensor and the second overlay correction pattern.

What is claimed is: 
     
       1. A masking process, comprising:
 aligning a first mask with a stage carrying a substrate to be patterned; 
 forming a first layer structure and a first overlay correction pattern on the substrate to be patterned by using the first mask; 
 correcting with an image sensor and the first overlay correction pattern; aligning a second mask with the stage; 
 forming a second layer structure and a second overlay correction pattern on the substrate to be patterned by using the second mask; and 
 correcting with the image sensor and the second overlay correction pattern. 
 
     
     
       2. The masking process according to  claim 1 , wherein a thickness of the first layer structure is greater than 5 times of a thickness of the second layer structure. 
     
     
       3. The masking process according to  claim 1 , wherein the first mask comprises a first mask pattern, a first alignment mark and a first overlay correction mark located at a periphery of the first mask pattern, the stage carrying the substrate to be patterned comprises a second alignment mark, and aligning the first mask with the stage carrying the substrate to be patterned comprises:
 using the first alignment mark and the second alignment mark to align the first mask with the stage carrying the substrate to be patterned. 
 
     
     
       4. The masking process according to  claim 3 , wherein forming the first layer structure and the first overlay correction pattern on the substrate to be patterned by using the first mask comprises:
 performing a patterning process using the first mask to form the first layer structure corresponding to the first mask pattern and the first overlay correction pattern corresponding to the first overlay correction mark on the substrate to be patterned. 
 
     
     
       5. The masking process according to  claim 1 , wherein the second mask comprises a second mask pattern, a third alignment mark and a second overlay correction mark located at a periphery of the second mask pattern, and aligning the second mask with the stage carrying the substrate to be patterned comprises:
 using the third alignment mark and the second alignment mark to align the second mask with the stage carrying the substrate to be patterned. 
 
     
     
       6. The masking process according to  claim 5 , wherein forming the second layer structure and the second overlay correction pattern on the substrate to be patterned by using the second mask comprises:
 performing a patterning process using the second mask to form the second layer structure corresponding to the second mask pattern and the second overlay correction pattern corresponding to the second overlay correction mark on the substrate to be patterned. 
 
     
     
       7. The masking process according to  claim 1 , wherein
 correcting with the image sensor and the first overlay correction pattern comprises: acquiring an image of the first overlay correction pattern by using the image sensor; and adjusting parameters of an exposure machine according to distortion condition of the image of the first overlay correction pattern, 
 correcting with the image sensor and the second overlay correction pattern comprises: acquiring an image of the second overlay correction pattern by using the image sensor; and adjusting parameters of the exposure machine according to distortion condition of the image of the second overlay correction pattern. 
 
     
     
       8. The masking process according to  claim 1 , wherein the second mask further comprises an automatic distortion control mark, and the masking process further comprises:
 performing a patterning process using the second mask to form an automatic distortion control pattern corresponding to the automatic distortion control mark on the substrate to be patterned. 
 
     
     
       9. The masking process according to  claim 8 , further comprising:
 aligning a third mask with the substrate to be patterned,
 wherein the third mask comprises a fourth alignment mark, and the third mask is aligned with the substrate to be patterned by using the fourth alignment mark and the automatic distortion control pattern. 
 
 
     
     
       10. The masking process according to  claim 8 , wherein the automatic distortion control pattern is formed simultaneously with the second layer structure and the second overlay correction pattern. 
     
     
       11. The masking process according to  claim 8 , wherein the automatic distortion control pattern is on a same layer as the second layer structure and the second overlay correction pattern.